Few days urinating quite more than water intake,followed by days urinating extremely lower than intake which causes dark urine and bladder irritation.normal bloodwork and egfr. in both cases,same intake,no physical activity.what can be the reason?

I answered your question last week. As long as you kidney function and electrolytes are normal then you have nothing to worry. I also stated that it will be interested to have your blood and urine test done on the day with darker urine to confirm you are low in volume on that day. Take care.

Amount voided involves many things besides water intake eg weather, temperature, alcohol, caffeinated beverages, exercise, bowel movements, infection etc.. If Kidney function is normal then there is no Kidney cause. If symptoms persist pl see a Urologist. In the meantime you can measure the amount ingested and voided accurately to avoid guessing. Good luck